Somehow, when reading a thriller these days, one has the impression that one is experiencing a film rather than picking up a book. This is particularly true when reading Michael Crichton, who seems to have been involved in about 15 of the most popular films of all time. So it is no insult to him, or none intended, when I say that no one is going to mistake Prey for literature. How can the hero be shown around the top-secret factory, having sprinkler systems and open-caged lifts pointed out to him, without us understanding it as a guarantee that such systems will prove crucial come the final showdown?

Which, I may say, the average reader will be in a hurry to get to. The novel may be 360-odd pages long, but it shouldn't take more than three hours to finish. This is a function not only of Crichton's utterly frictionless, deliberately unremarkable prose, but of your desire to see How They're Going To Get Out Of This One.

It is a great idea; it will make a great film. Our hero, Jack, was a Silicon Valley computer programmer, working on those awfully clever programs which try to teach computers to fix themselves - the kind of artificial intelligence which operates from very basic principles rather than complex ones. (You'll find the science presented just as bafflingly, if more plausibly, in the book itself.) However, he was sacked from his job for discovering corruption high up; and now he is unemployable, so he looks after the three kids while his wife does high-profile PR for a company working in nanotechnology.

She starts coming home late. She's looking different. Better groomed, sleeker. She has a shower the moment she comes in rather than in the morning, like she used to. What's going on? An affair, obviously. But then the baby develops a painful rash and no one can figure out what the hell is wrong. Just as suddenly, the rash vanishes. Meanwhile, the eight-year-old's MP3 player stops working; Jack finds the memory chip has been turned to dust. He discovers what looks like a surge suppressor in the kids' bedroom. Only it's not. His wife starts acting really weird.

This is all paced extremely well. Jack comes to realise that he is dealing with something extremely dangerous, and with the hints we are offered, we find ourselves being given the heeby-jeebies pretty comprehensively. Scaring us via the kids is always a good way to do this. The middle child mentions that, while Jack was at the hospital with the baby, the house was visited by "vacuum men", as well as a ghost. "All silver and shimmery, except he didn't have a face." It is part not so much of our expectations as our demands of such a story that the father routinely dismisses this as a movie-induced nightmare rather than the significant testimony we immediately understand it to be. (In a sense, the whole novel is a movie-induced nightmare, so everyone's happy - including men who make a big deal about doing childcare, for even they get to save the world.)

Crichton dresses up his stories in contemporary clothes, and the nature of the threat is as much a wardrobe decision as anything else. It is, in fact, the key decision, and his alighting on nanotechnology is inspired. This is techie stuff new enough for the word not to be recognised by my WP package. It also sounds extremely hairy - imagine billions of flying molecule-sized particles programmed to work together, learn, and evolve at great speed. Crichton has. I am doubtful as to whether the form this emergent intelligence takes would so precisely mimic the actions of something out of Terminator II , but the principle is scary enough. Almost as scary as Crichton's photograph on the book jacket. He's meant to be 60, for crying out loud. There's something really sinister going on there. Someone should check him out.